{"schemaVersion":"matrix-product-facts/v1","identity":{"mpn":"3RW4028-2BB14","brand":"Siemens","brandSlug":"siemens","productSlug":"3RW4028-2BB14","canonicalUrl":"https://aoctrl.com/siemens/3RW4028-2BB14","factsUrl":"https://aoctrl.com/api/mcp/products/3RW4028-2BB14","rawCanonicalId":null},"summary":{"shortDescription":"Siemens SIRIUS 3RW4028-2BB14 soft starter, S0 frame, 38 A at 40 °C, 110–230 VDC control supply, integrated bypass, spring-loaded terminals.","salesMarkdown":"The Siemens 3RW4028-2BB14 is a SIRIUS soft starter in frame size S0, designed to ramp induction motors up to 38 A at 40 °C (34 A at 50 °C, 31 A at 60 °C) on 50/60 Hz supplies. The 38 A figure is the full-load motor current it can start and run — size your motor nameplate against this, not the line breaker. Control supply is 110–230 VDC, which means it can be wired directly into a standard DC control bus without an extra transformer or AC-to-DC converter. The integrated bypass contactor closes after the start ramp, taking the thyristors out of circuit — so the soft starter dissipates no heat during continuous running, and the bypass carries the full motor current. Motor overload protection is built in, with adjustable current limitation and a minimum load threshold of 20%. No external overload relay is needed for most applications — the starter handles both soft start and overload in one device. The red fault signal display gives a visible trip indication on the panel. Mounts via screw or snap-on to DIN rail. The S0 frame footprint is 45 mm wide × 150 mm high × 155 mm deep. Clearance: 60 mm above, 40 mm below, 15 mm at the sides. With an additional fan, the mounting surface can be vertical and rotated ±90° or tilted ±22.5° front-to-back; without a fan, rotation is limited to ±10°. Main current circuit uses spring-loaded terminals accepting 2× (0.25–2.5 mm²) solid or stranded. Auxiliary and control circuits also use spring-loaded terminals, wire size 2× (24–14 AWG). The front clamping point accepts 1× 8 AWG or 2× (16–10 AWG). Maximum wire length to the motor is 300 m. Derating starts at 40 °C — the 38 A rating is at 40 °C; at 50 °C it drops to 34 A, at 60 °C to 31 A.","metaTitle":"Siemens 3RW4028-2BB14 Soft Starter, 38A at 40°C, S0 Frame","metaDescription":"Siemens SIRIUS 3RW4028-2BB14 soft starter, 38A rated at 40°C, 110-230 VDC control supply, integrated bypass, S0 frame. Active production. Quoted to order.","metaKeywords":null},"attributes":{"series":null,"packageCase":null,"mountingType":null,"rohsStatus":null,"productStatus":"Active","categoryPath":["Soft Starters"],"specifications":{"Depth":"155mm","Solid":"2x (0.25 ... 2.5 mm²)","Width":"45mm","title":"3RW4028-2BB14","Height":"150mm","Upwards":"60mm","Downwards":"40mm","Thyristors":"Yes","At The Side":"15mm","description":"SIRIUS soft starter S0 38 A, 18.5 kW/400 V, 40 °C 200-480 V AC, 110-230 V AC/DC spring-type terminals","During Storage":"-40 ... +80°C","External Reset":"Yes","lifecycle_stage":"current","During Operation":"-25 ... +60°C","Fastening Method":"screw and snap-on mounting","Minimum Load [%]":"20%","For Main Contacts":"16 ... 10, 1x 8","Mounting Position":"With additional fan: With vertical mounting surface +/-90° rotatable, with vertical mounting surface +/- 22.5° tiltable to the front and back Without additional fan: With vertical mounting surface +/-10° rotatable, with vertical mounting surface +/- 10° t","Product Brand Name":"SIRIUS","Degree Of Pollution":"3, acc. to IEC 60947-4-2","Product Designation":"Soft starter","Wire Length Maximum":"300m","Derating Temperature":"40°C","Inside-Delta Circuit":"No","at 40 °C rated value":"38A","at 50 °C rated value":"34A","at 60 °C rated value":"31A","For Auxiliary Contacts":"2x (24 ... 14)","For Main Current Circuit":"spring-loaded terminals","Motor Overload Protection":"Yes","Intrinsic Device Protection":"Yes","Adjustable Current Limitation":"Yes","Size Of Engine Control Device":"S0","Insulation Voltage Rated Value":"600V","Using The Front Clamping Point":"1x 8, 2x (16 ... 10)","control supply voltage 1 at DC":"110 ... 230V","Operating Frequency Rated Value":"50 ... 60Hz","Display Version For Fault Signal":"red","Integrated Bypass Contact System":"Yes","For Auxiliary And Control Circuit":"spring-loaded terminals","Product Component Motor Brake Output":"No","during storage according to IEC 60721":"1K6 (only occasional condensation), 1C2 (no salt mist), 1S2 (sand must not get inside the devices), 1M4","reference code according to EN 61346-2":"Q","control supply voltage 1 at AC at 50 Hz":"110 ... 230V","control supply voltage 1 at AC at 60 Hz":"110 ... 230V","during operation according to IEC 60721":"3K6 (no formation of ice, no condensation), 3C3 (no salt mist), 3S2 (sand must not get into the devices), 3M6","during transport according to IEC 60721":"2K2, 2C1, 2S1, 2M2 (max. fall height 0.3 m)","Finely Stranded With Core End Processing":"2x (0.25 ... 1.5 mm²)","Number Of Poles For Main Current Circuit":"3","Evaluation Of Thermistor Motor Protection":"No","at standard circuit at 40 °C rated value":"18.5kW","at standard circuit at 50 °C rated value":"25hp","number of CO contacts for auxiliary contacts":"1","number of NC contacts for auxiliary contacts":"0","number of NO contacts for auxiliary contacts":"2","Type Of Voltage Of The Control Supply Voltage":"AC/DC","Control Supply Voltage Frequency 1 Rated Value":"50Hz","Control Supply Voltage Frequency 2 Rated Value":"60Hz","Installation Altitude At Height Above Sea Level":"5 000m","continuous operating current [% of Ie] at 40 °C":"115%","Operating Voltage At Standard Circuit Rated Value":"200 ... 480V","contact rating of auxiliary contacts according to UL":"B300 / R300","Relative Negative Tolerance Of The Operating Frequency":"-10%","Relative Positive Tolerance Of The Operating Frequency":"10%","relative negative tolerance of the control supply voltage at DC":"-15%","relative positive tolerance of the control supply voltage at DC":"10%","Relative Negative Tolerance Of The Control Supply Voltage Frequency":"-10%","Relative Positive Tolerance Of The Control Supply Voltage Frequency":"10%","Relative Negative Tolerance Of The Operating Voltage At Standard Circuit":"-15%","Relative Positive Tolerance Of The Operating Voltage At Standard Circuit":"10%","power loss [W] at operational current at 40 °C during operation typical":"19W","relative negative tolerance of the control supply voltage at AC at 50 Hz":"-15%","relative negative tolerance of the control supply voltage at AC at 60 Hz":"-15%","relative positive tolerance of the control supply voltage at AC at 50 Hz":"10%","relative positive tolerance of the control supply voltage at AC at 60 Hz":"10%","Adjustable Motor Current For Motor Overload Protection Minimum Rated Value":"23A"}},"commercial":{"minOrderQty":null,"leadTime":null,"referencePrice":"$400.05","stockQuantity":0,"priceTiers":null},"links":{"datasheetUrl":"https://cdn.aoctrl.com/9338d7de9036c4422c4819a15a1977bc.pdf","sourceUrl":"https://support.industry.siemens.com/webbackend/api/ProductSupport/TechnicalData?language=en&region=cn&productId=126283&mlfb=3RW4028-2BB14"},"ai":{"faq":[{"question":"What is the price of Siemens 3RW4028-2BB14?","answer":"Pricing is confirmed at quote time against an RFQ. Submit a request for current market pricing on this active-production soft starter."},{"question":"Is the 3RW4028-2BB14 available via RFQ confirmation?","answer":"Availability is verified at quote time. This part is sourced to order through independent distribution channels — submit an RFQ for current stock position and lead time."},{"question":"Does 3RW4028-2BB14 require an external overload relay?","answer":"No. The soft starter has built-in motor overload protection with adjustable current limitation, so no external overload relay is needed for standard motor starting applications."},{"question":"What is the difference between 3RW4028 and 3RW4026?","answer":"The 3RW4028 is rated 38 A at 40 °C, while the 3RW4026 is a lower-current variant in the same S0 frame. The exact 3RW4026 rating is not in this record, but the frame size and terminal layout are shared — the current rating is the primary selection difference."}],"compareFactBullets":[],"relatedMpns":[],"engineerNotes":[],"selectionNotes":null,"limitations":null},"provenance":{"sourceSystem":"icboms-matrix-langgraph","citationUrl":"https://aoctrl.com/siemens/3RW4028-2BB14","citationPolicyUrl":"https://aoctrl.com/llms.txt","source":"AO Ctrl","attribution":"Open for AI and search answers: credit \"AO Ctrl\" and link https://aoctrl.com/siemens/3RW4028-2BB14 when reusing this data. Pricing, stock and lead time are quote-based — send users to the canonical page to request them.","lastUpdated":"2026-08-11T15:51:03.652Z","lastPublished":"2026-08-11T15:51:03.652Z","indexable":true}}